Switching between UV maps on a single object
I find it's easiest to do this in Blender Render. (Green oval).

You only need one material and one texture, but a UV map for each couch pattern. Here I have 3 couch patterns so I'm using 3 UV maps. (Magenta circles).

Unwrap the couch for each pattern. For the red, I've used project from view. You can then scale and manipulate the mesh (in UV/Image editor) to reflect how you'd it displayed. (Red ovals).



Do this this for each couch pattern, but make sure the correct UV Map is selected and the corresponding image is loaded in the UV/Image editor. (Purple ovals). For the pink couch pattern, I've used "Sphere Projection" unwrap.



Switching between the UV Maps in the properties window (magenta circle) will switch between the patterns and how you've set them up.

In Cycles:

Add the following nodes (You can easily do this by hitting spacebar and typing in the node name): UV Map (so blender knows what mesh coordinates to use), Image Texture (so blender knows what image to use), Diffuse (so there's actually light to see the image) and then Material Output.

Then follow the steps in red to switch between couch patterns.